Synchronous Physical-Layer Network Coding: A Feasibility Study

Recently, Physical-layer Network Coding (PNC) attracts much attention due to its ability to improve throughput in relay-aided communications. However, the implementation of PNC is still a work in progress, and synchronization is a significant and difficult issue. This paper investigates the feasibility of synchronous PNC with M-ary Quadrature Amplitude Modulation (M-QAM). The authors first propose a synchronization scheme for PNC. Then, they analyze the synchronization errors and overhead of potential synchronization techniques, which includes Phase-Locked Loop (PLL) and Maximum Likelihood Estimation (MLE) based synchronization schemes. Their effects on the average symbol error rate and the good put are subsequently discussed.